Organosiloxane resins containing as substituents (ch3)2 sich2-or (ch3)2 c6h5sich2



Patented Apr. 1, 1952 ORGANOS-ILOXANE RESINS CONTAIN- ING AS SUBSTITUENTS (CH3)SiCH2- OR. -(CH3)2C6H5SiCH2 John T. Goodwin, Jr., Midland, Mich., assignor to Dow Corning Corporation, Midland, Mich., a corporation of Michigan No Drawing. :Application May 1, 1950, Serial No. 159,393

3 Claims. (Cl. 26046.5)

.1 .Thepresent .invention relates to new 'organosilicon resins and to their method of production.

Therpresent invention is acontinuation inpart of mycopendingapplication, Serial .No. 82,475, filed March 19, 1949 now U. S. Patent No. 2,507,518.

The present organosilicon industry is based upon .siloxanes which arem-aterials in which the silicon atoms are linked vthroughoxygen atoms. Another .type of "compound is one inwhich the silicon atoms are linked directly to each other. Still a'third type is'one'in which the silicon atoms are linked by organic radicals. The literature presents very little information about this last type of compound.

Objects of the present invention are to produce organosiloxane resins in which some of the silicon atoms are bonded to triorganosilylmethyl radicals. Other objects and advantages of the present invention will be apparent from the iollowingdescription and the vsubjoined claims.

In accord with the present invention a compound of the formula RSiCh and a composition of the average formula R'nsiCLi-n are co-hydrolyzed by reacting water with a mixture thereof and the reaction product thereof cocondensed. In the above formula, R is a substituent selected from the group consisting of (CH3)3SlCH2-- and (CH3) 2CsH5SiCHz-, R is selected from the group eonsistingof alkyl and monocyclicaryl radicals and n has an average value of from 1 to 2 inclusive. There is thereby produced an organosilicon resin containing units of the formula RSiO1.5 and R,,Si T

In this resin, the ratio of R-l-R' to Si is from 1 to 1.6 inclusive, and the said units are connected by silicon-oxygen-silicon bonding. The compound of the formula (CI-b) 3SiCH2SiC13 may be produced by reacting SiC14 with (CI-Is) ssiCHzMgCl or (CH3)3SiCH2Li.

The organolithium compound, (CH3)3SiCI-I2Ll, may be prepared by gradually adding (CH3) BSiCHZCl to an equivalent weight of a finely divided suspension of lithium in mineral oil.

The Grignard reagent, (CHslsSiCHzMgCl, may be prepared by reacting magnesium with an tion of an organic layer.

equivalent-weight of chloromethyltrimethylsilane in ether solution.

Similarly, the reactant, (CHs)zCsH5SiCH-2SiC1a; may be prepared by substituting (CH3) zCsHsSiCHzCl for the (CH3')3SiCH2Cl reactant.

To assure a high yield of the desired product, (CH3)3SiCH2SiC13 or (CH3)2CsH5SiCH2SiC13, the organometallic compound is employedin proportion of 0.5 to less than 3 molar equivalents per mol of silicon tetrachloride. Preferably equimolecular amounts are employed. The reaction may be carried out by mixing the organometallic compound with the silicon tetrachloride. The resulting product may be purified by filtering and distilling as desired. f

The hydrolysis of the organosilicon compositions to produce copolymer resins maybe carried out by cohydrolyzingby reacting water with a mixture of RSiCls and R'nsiC14n and cocondensing the reaction product thereof. In such a process, the reaction may be carried out in the presence of a solvent such as toluene. The hydrolyzing and cocondensing may be carried out at a temperature of between 0 C. and 250 C.

The resins of the present invention are of utility in formulating heat and weather resistant coatings for boilers, stacks, ovens and other hot metal surfaces.

Example 1 When 245 parts by weight of (CH3)3SiCHzC1 is added to 48 parts of magnesium in ethyl ether,

(CI-I3)3SiCH2MgCl is obtained. The Grignard reagent so prepared is added to 680 parts of sili con tetrachloride. The reactants couple readily at room temperature. The product is filtered, and the filtrate transferred to a stripping still and the ether stripped ofi. Distillation yields 255, parts of the compound (CH3)3SiCH2SiC13. The compound has a boiling point of 165.8 C. at atmospheric pressure, a density of 1.1234 at 25 C., a refractive index of 1.4448 at 25 C., and a specific refraction of 0.2368.

When a mixture of 149.5 parts of CI-IsSlCls, 221.5 parts of (CH3)3SiCH2SiC13 and 191 parts of CsHsCHsSiClz is gradually added during one-half hour to 635 parts of toluene in 1168 parts of H20, hydrolysis occurs with the separa- This organic layer is decanted and shaken with NaHCO3. It is then washed, filtered, and concentrated to 35 per cent solids. The resulting composition will be upon drying a tough, flexible resin.

Example 2 When silicon tetrachloride in amount of 170 parts by weight is gradually added over a period of one hour to 84 parts of the organolithium compound, (CI-I3)3SiCI-I2Li, dissolved in pentanv coupling occurs with the production of (CH3) 3SiCH2SiC13 Example 3 When 239.9 parts of CsH5(CH3)2SiCH2Cl are added to 32 parts by weight of magnesium and 300 parts of ethyl ether, reaction occurs. 700 parts of ethyl ether are then added and the mixture stirred. The resulting Grignard reagent is CeH5(CH3)2SiCH2MgC1.

1000 parts of toluene and 500 parts of SiCl4 are mixed and the Grignard reagent CsHs (CH3) 2SiCH2MgC1 added. The reaction mixture is stirred for hours. The reaction mass is filtered and stripped of toluene. The residue is distilled, and 177 parts of the product C6H5(CH3)2SiCH2SiC13 are obtained. This compound has a boiling point of 146 C. at mm., a refractive index of 15174 at C., a density of 1.187 at 25 C. and a specific refraction of 0.3028.

When 47 parts of this product,

(CH3) zCsHsSiCHzSiCls 35 parts of CeHsSiCla and parts of CHzSiCh are mixed and added to 232 parts of toluene, and the resulting solution added to 32 parts of water in 27.2 parts of isopropyl alcohol, hydrolysis occurs with phase separation. The reaction mixture is decanted. The water insoluble layer is refluxed for two hours and then washed, following which the resin is concentrated to 30 per cent solids. The resulting composition upon drying will be a tough, flexible resin.

That which is claimed is:

1. An organosilicon copolymer resin containing units of the formula RSiO1.5 and where R is a substituent selected from the group consisting of (CH3)3SiCH2 and (CH3) 2CsH5SiCH2- R is a radical selected from the group consisting of alkyl and monocyclicaryl radicals, and n has an average value of from 1 to 2 inclusive, the remaining valences of the silicon atoms of said units being satisfied by oxygen atoms, in which the ratio of R+R to Si is from 1 to 1.6 inclusive. and in which, the said units are connected by silicon-oxygen-silicon bonding.

2. A copolymer resin in accord with claim 1 in which R is (CH3) 3SiCHz-.

3. A copolymer resin in accord with claim 1 in which R is (CI-I3) 2CsH5SiCH2.

JOHN T. GOODWIN, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,486,162 Hyde Oct. 25, 1949 2,507,518 Goodwin May 16, 1950 

1. AN ORGANOSILICON COPOLYMER RESIN CONTAINING UNITS OF THE FORMULA RSIO1.5 AND 